This invention relates to a hammer system, and more particularly relates to a hammer system for use in conjunction with a compartmented rotary cement metering drum.
Cement is a hygroscopic material and consequently any cement metering system must have provisions for breaking loose any caking of the cement on the metering surface. Various prior art devices have been developed to break loose caked cement. Generally, these devices are in the form of a hammering system.
A number of these hammer systems shake or beat the entire bin from which the cement is to be metered. Such systems waste energy insofar as the cement which is caked on the metering system is concerned because the vibrations generated by the beating are not specifically directed at the point at which the problem is most acute, namely, in the metering system itself. A prior art hammer system which is specifically directed at breaking loose caked cement in the metering system is shown in commonly assigned U.S. Pat. No. 3,336,011. This system comprises spring elements, hammer elements supported on one end of the spring elements, and a shaft upon which the spring elements are fixed. The hammer elements are bised into engagement with the surface of a compartmented rotary metering drum having vanes which are provided with inclined plane surfaces. As the drum rotates, the hammer elements are displaced by the inclined surfaces thereby causing the springs to be placed under added stress. As the metering drum continues to rotate, the hammer members are freed from engagement with the inclined plane surfaces and impart a hammer blow to the metering drum releasing any cement which may have become caked thereon. Although this system is commercially useful, it suffers from a number of disadvantages. The spring elements after numerous cycles of operation tend to lose their spring and/or break. The breakage most often occurs at the junction of the hammer element with the spring element. High-quality spring steel is necessary to manufacture the spring elements and thus they are costly to replace. Additionally, a hammer system of this nature is inherently not adjustable.